Vulnerability Report

CVE-2026-33806

Title: Fastify Content-Type Validation Bypass

Other

Proof Of Concept

No public PoC currently indexed for CVE-2026-33806.

CWE Category CWE-1287

Published Date Apr 15, 2026

Modified Date Apr 17, 2026

Exploit Status Not Found

Score 7.5 CVSS v3.1

Exploit Probability (EPSS)

0.11%

Vulnerability Summary

CVE-2026-33806: Impact: Fastify applications using schema.body.content for per-content-type body validation can have validation bypassed entirely by prepending a space to the Content-Type header. The body is still parsed correctly but schema validation is skipped. This is a regression introduced in fastify >= 5.3.2 by the fix for CVE-2025-32442 Patches: Upgrade to fastify v5.8.5 or later. Workarounds: None. Upgrade to the patched version.

Impacted Vendors

fastify 1

Reference Links

https://cna.openjsf.org/security-advisories.html https://github.com/fastify/fastify/security/advisories/GHSA-mg2h-6x62-wpwc

CVSS v3.1

Source Entity ce714d77-add3-4f53-aff5-83d477b104bb

Severity HIGH

7.5

Attack Vector

NETWORK

Complexity

LOW

Privileges

N/A

Interaction

NONE

Confidentiality

N/A

Integrity

N/A

Availability

N/A

Scope

UNCHANGED

RAW VECTOR CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Associated Attack Patterns (CAPEC)

Total: Patterns

CVE-2026-33806 Exploits & PoCs (Proof Of Concept)

No public PoCs found in our database for this CVE.

April 17, 2026 MODIFIED

Vulnerability data updated via NVD.

April 17, 2026 MODIFIED

Vulnerability data updated via NVD.

Attack Vector Matrix

Access Vector NETWORK

Complexity LOW

Privileges N/A

Interaction NONE

CVSS Vector String


                                    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Affected Stack

No specific products linked.